Research on Background Learning Correlation Filtering Algorithm With Multi-Feature Fusion

Aiming at the problems of occlusion, drift, and background change in visual image tracking, a background learning correlation filtering algorithm based on multi-feature fusion is proposed. In the framework of correlation filtering, multi-feature fusion, multi-template update, and background learning regularization are used to improve the performance of the filter in the problem of template contamination and object occlusion. The fast directional gradient histogram (FHOG), color feature (CN), and texture feature (ULBP) were extracted, and the feature channels were connected in series. Then the depth features of Conv4-4 and Conv5-4 layers were extracted through the VGG-19 network, and the appearance model of the target was constructed. To reduce the sensitivity of the filter to the sudden change of background, a background learning filter is constructed, and the alternate direction multiplier method (ADMM) is used to speed up the calculation of the filter. In the model update stage, aiming at the problem of pollution of the original template caused by target occlusion, a high-confidence multi-template fusion update strategy is proposed by fusing the template with the highest confidence in the current frame, the previous frame, and the history frame. Finally, the proposed algorithm is tested on OTB50, OTB100, UAV123, and TC128 experimental data sets, and some classical and latest algorithms. The experimental results show that the tracking accuracy and robustness of the correlation filtering algorithm are improved

Low-Coordinate Iridium Oxide Confined on Graphitic Carbon Nitride for Highly Efficient Oxygen Evolution

Highly active and durable electrocatalysts for the oxygen evolution reaction (OER) is greatly desired. Iridium oxide/graphitic carbon nitride (IrO2/GCN) heterostructures are designed with low-coordinate IrO2 nanoparticles (NPs) confined on superhydrophilic highly stable GCN nanosheets for efficient acidic OER. The GCN nanosheets not only ensure the homogeneous distribution and confinement of IrO2 NPs but also endows the heterostructured catalyst system with a superhydrophilic surface, which can maximize the exposure of active sites and promotes mass diffusion. The coordination number of Ir atoms is decreased owing to the strong interaction between IrO2 and GCN, leading to lattice strain and increment of electron density around Ir sites and hence modulating the attachment between the catalyst and reaction intermediates. The optimized IrO2/GCN heterostructure delivers not only by far the highest mass activity among the reported IrO2-based catalysts but also decent durability

Macromolecular Design for Oxygen/Nitrogen Permselective Membranes—Top-Performing Polymers in 2020—

Oxygen/nitrogen permselective membranes play particularly important roles in fundamental scientific studies and in a number of applications in industrial chemistry, but have not yet fulfilled their full potential. Organic polymers are the main materials used for such membranes because of the possibility of using sophisticated techniques of precise molecular design and their ready processability for making thin and large self-supporting membranes. However, since the difference in the properties of oxygen and nitrogen gas molecules is quite small, for example, their kinetic diameters are 3.46 Å and 3.64 Å, respectively, the architectures of the membrane macromolecules should be designed precisely. It has been reported often that oxygen permeability (PO2) and oxygen permselectivity (α = PO2/PN2) have trade-off relationships for symmetric membranes made from pure polymers. Some empirical upper bound lines have been reported in (ln α − ln PO2) plots since Robeson reported an upper bound line in 1991 for the first time. The main purpose of this review is to discuss suitable macromolecular structures that produce excellent oxygen/nitrogen permselective membranes. For this purpose, we first searched extensively and intensively for papers which had reported α and PO2 values through symmetric dense membranes from pure polymers. Then, we examined the chemical structures of the polymers showing the top performances in (ln α − ln PO2) plots, using their aged performances. Furthermore, we also explored progress in the molecular design in this field by comparing the best polymers reported by 2013 and those subsequently found up to now (2020) because of the rapid outstanding growth in this period. Finally, we discussed how to improve α and PO2 simultaneously on the basis of reported results using not only symmetric membranes of pure organic polymers but also composite asymmetric membranes containing various additives

Transmission Enhancement through Sub-Wavelength Aperture Based on Regulable Water-Based Metamaterial

A realization form of the Mie resonance with adjustable characteristics based on a water-based metamaterial is proposed. A novel local electromagnetic field coupling mechanism based on a water-based metamaterial is established, which is used for transmission enhancement through the sub-wavelength aperture for the first time. The water-based metamaterial particle for transmission enhancement at a specific frequency is designed. By designing the microfluidic control system to control the water filling (i.e., height) of the metamaterial particle, the adjustable transmission enhancement characteristics are realized. The influence of bilateral symmetry and flexible deformation of the metamaterial particle on the transmission characteristics is analyzed. The influence of the design parameters on the enhanced transmission characteristics is discussed

Transmission Enhancement through Sub-Wavelength Aperture Based on Regulable Water-Based Metamaterial

A realization form of the Mie resonance with adjustable characteristics based on a water-based metamaterial is proposed. A novel local electromagnetic field coupling mechanism based on a water-based metamaterial is established, which is used for transmission enhancement through the sub-wavelength aperture for the first time. The water-based metamaterial particle for transmission enhancement at a specific frequency is designed. By designing the microfluidic control system to control the water filling (i.e., height) of the metamaterial particle, the adjustable transmission enhancement characteristics are realized. The influence of bilateral symmetry and flexible deformation of the metamaterial particle on the transmission characteristics is analyzed. The influence of the design parameters on the enhanced transmission characteristics is discussed

Anion-exchange membrane water electrolyzers and fuel cells

Anion-exchange membrane (AEM) water electrolyzers (AEMWEs) and fuel cells (AEMFCs) are technologies that, respectively, achieve transformation and utilization of renewable resources in the form of green hydrogen (H2) energy. The significantly reduced cost of their key components (membranes, electrocatalysts, bipolar plates, etc.), quick reaction kinetics, and fewer corrosion problems endow AEM water electrolyzers and fuel cells with overwhelming superiority over their conventional counterparts (e.g., proton-exchange membrane water electrolyzer/fuel cells and alkaline water electrolyzer/fuel cells). Limitations in our fundamental understanding of AEM devices, however, specifically in key components, working management, and operation monitoring, restrict the improvement of cell performance, and they further impede the deployment of AEM water electrolyzers and fuel cells. Therefore, a panoramic view to outline the fundamentals, technological progress, and future perspectives on AEMWEs and AEMFCs is presented. The objective of this review is to (1) present a timely overview of the market development status of green hydrogen technology that is closely associated with AEMWEs (hydrogen production) and AEMFCs (hydrogen utilization); (2) provide an in-depth and comprehensive analysis of AEMWEs and AEMFCs from the viewpoint of all key components (e.g., membranes, ionomers, catalysts, gas diffusion layers, bipolar plates, and membrane electrode assembly (MEA)); (3) summarize the state-of-the-art technologies for working management of AEMWEs and AEMFCs, including electrolyte engineering (electrolyte selection and feeding), water management, gas and heat management, etc.; (4) outline the advances in monitoring the operations of AEMWEs and AEMFCs, which include microscopic and spectroscopic techniques and beyond; and (5) present key aspects that need to be further studied from the perspective of science and engineering to accelerate the deployment of AEMWEs and AEMFCs